Fallen Knight

7) Mythical (this map will humiliate your years of experience playing Heroes. Completing it is an act of masochism, and victory is comparable to a miracle. At least, without detailed knowledge of how to complete it).

I don't play much, but I've encountered such maps and quit before finishing them. They are off-putting from the start.
The authors deliberately make it difficult by giving the player an army of one and a half "invalids" and forcing them to try to break down overwhelming stacks throughout the game, getting bogged down in endless loading screens, like a schizophrenic repeating the same action, hoping for a different result. For such victories, they gave only meager experience. The enjoyment level is 0. The experience gained here has no relation to completing the map.